Chalk-eraser



GON.

(No Mbdl.)

W. H. LONDER 'GHALK ERAS Patented Apr. 2', 1889.

: UNITED STATES PATENT CFFmE.

WILLIAM II. LONDERGON, OF LAKE, ILLINOIS.

CHALK-ERASER.

SPECIFICATION forming part of Letters Patent No. 400,465, dated April 2, 1889.

Application filed November 19, 1888. $erial No. 291,209. (No model.)

To all whom it may concern:

Be it known that I, WILLIAM H. LONDER- GON, a citizen of the United States, residing in the townof Lake,in the county of Cook and State of Illinois, have invented a new and useful Improvement in Chalk-Erasers, of

which the following is a specification.

Theobject of my invention is to make a simple, economical eraser for use on blackboards in schools, 850. and the invention consists in the features and combinations hereinafter described and claimed.

' In the accompanying drawings, Figure 1 is a perspective View of my improved chalkeraser; Fig. 2, across-section of the same; and Fig. 3, aperspective view of part of the handleblock.

A is the block or wooden part, and a little ribs or ridges on the surface thereof; 13, the side strips; 0, the cross-strips, and D the spaces between the cross-strips.

In constructing my improved eraser I glue two strips of felt or similar material lengthwise of the block of wood, one at each edge, and between these two strips I place any desired number of short strips, preferably, but not necessarily, of the same material, which are also glued to the wood. For ordinary erasers it will be convenient to have the felt strips from a quarter to half an inch thick, and of about the same width; but they may be larger or smaller, and of course they may be of any length desired, according to the'size of the eraser in which they are being used.

In addition'to being glued to the wood,the erasing material is further secured by means of the little ridges and channels formed in the surface of the block. Such material being soft, is pressed down into these little channels, and in this way much more firmly held in place than is possible when it is merely glued onto a smooth surface. In fact, I have found it almost impossible to secure the erasing material in a practical way on a smooth surface, or one having no'ribs, ridges, or projections to aid in holding it in place. The

little channels, however, should not be so deep as to receive a considerable portion of the erasing material, and thus cause the same to be lost or wasted whenever the outer part is worn off by use; but, as above suggested,

they are intended to be quite smallonlylarge enough to roughen the surface-to aid in securing the felt, as above described.

The short strips of felt secured between the long ones, extending cross-wise of the roughened surface, are so placed as to form spaces or crevices which receive or take up the powdered chalk erased from the blackboard; and of course each of these strips forms or has an independent surface of its own, which rubs against the board and aids in the erasing. It is desirable that the ends of all the cross strips should press snugly against the side strips; but this is especially necessary of the cross-strips at the ends, inasmuch as thus pressing snugly against the side strips they form practically tight joints, and prevent the powdered chalk from working out or escaping at the ends of the erasers. The felt forming the erasing-surface is cut across its fiber, and thus put on in the most durable Way possible.

It will be noticed that the felt strips of my eraser, put on as above described, form square corners, which may be used to erase marks near the edges of the board, vor in places to which the general surface of the eraser is inapplicable.

It will also be noticed that the construction of my improved eraser, in which the larger part of the erasing-surface is formed from short strips, is such as to enable me to use scrap-felt of the kind that is generally sold as waste along with old paper, &c.; and, so far as I know, such scrap-felt cannot be used in the manufacture of any other eraser now in the market.

I am aware of the Joseph B. Walker patent of August 25, 187 4; but my eraser differs from the one described in this patent in that its felt strips are not secured in deep channels, and hence less erasing material is required, as, practically, the Whole of the erasing material can be worn out right up to the wood. I am also aware of the Herbert L. Andrews patent of May 15,1877; but my eraser differs from the one described in this patent in that it does not have any continuous outer strip, and its erasing material is not secured to a smooth surface. My eraser also differs from both of these patents, and similar old patents,

secured lengthwise thereon, and short strips of felt or similar material secured crosswise thereon at suitable distances apart, the crossstrips at each end coming up close to the side strips, whereby the erasing-surface is formed with square corners, tight joints at its corners, and spaces or crevices to receive the 20 chalk-dust, substantially as described.

WILLIAM H. LONDERGON.

Witnesses:

THOMAS A. BANNING, EPHRAIM BANNING. 

